1. Field of the Invention
The present invention relates to a vulcanizing machine, and more particularly to an improved tire vulcanizing machine for facilitating the loading a green tire into the tire vulcanizing machine.
2. Description of the Prior Art
At first, a tire vulcanizing machine in the prior art will be described with reference to FIG. 8. In this figure, reference numeral 01 designates a base, numeral 02 designates a frame provided on the base 01, numeral 02a designates a plurality of metal brackets projecting outwardly from an upper portion of the frame 02, numeral 03 designates a plurality of hydraulic cylinders (pressing means), numeral 03a designates clevises mounted to the top portions of the piston rods of the respective hydraulic cylinders, numeral 03c designates pins for pivotably supporting the clevises 03a on the aforementioned ear metals 02a, numeral 030 designates a lower ring, numeral 030a designates ribs projecting inwardly from the bottom portion of the lower ring 030, numeral 030b designates claws provided on the inner surface of the top portion of the lower ring 030, numeral 03d designates bolts for fixedly securing flanges 03b of the above-mentioned hydraulic cylinders 03 to the ribs 030a of the aforementioned lower ring 030, numeral 06' designates a lower heat insulator plate fixedly secured to the upper surface of the above-mentioned frame 02, numeral 06 designates a lower heater plate fixedly secured to the upper surface of the lower heat insulator plate 06', numeral 07 designates a lower mold fixedly secured to the upper surface of the lower heat insulator plate 06, numeral 034 designates a hydraulic cylinder, numeral 034a designates a clevis mounted to the lower end portion of a piston rod of the same hydraulic cylinder 034, numeral 09 designates a bolster, numeral 09a designates a metal bracket fixedly secured to the same bolster 09, numeral 033 designates a pin for pivotably supporting the above-mentioned clevis 034a on the metal bracket 09a, numeral 010' designates an upper heat insulating plate fixedly secured to the aforementioned bolster 09, numeral 010 designates an upper heater plate fixedly secured to the lower surface of the upper heat insulating plate 010', numeral 011 designates an upper mold fixedly secured to the lower surface of the upper heater plate 010, numeral 031 designates an upper ring, and numeral 031a designates a step portion formed at the top of the upper ring 031. The upper ring 031 is rotatably supported by the same step portion 031a being engaged with a step portion of the bolster 09. In addition, reference numeral 031b designates claws provided on the outer surface of the lower end portion of the upper ring 030, numeral 031c designates a pin provided on the upper surface of the upper ring 031, numeral 032 designates a hydraulic cylinder mounted to the frame, and numeral 032a designates a clevis mounted to a tip end portion of a piston rod of the aforementioned hydraulic cylinder 032. This clevis 032a is pivotably mounted to the aforementioned upper ring 031 via the pin 031c.
In the operation of the tire vulcanizing machine in the prior art which has the aforementioned construction, a green tire is set within the lower metal mold 07, then the bolster 09, the upper heat insulator plate 010', the upper heater plate 010, the upper metal mold 011 and the upper ring 031 are lowered to place the upper metal mold 011 on the lower metal mold 07 by extending the piston rod of the hydraulic cylinder 034. Subsequently, the piston rod of the hydraulic cylinder 032 is extended causing the upper ring 031 to rotate about its vertical axis due to the fact that the claws 031b provided on the outer surface of the lower end portion of the same upper ring 031 are engaged with the claws 030b provided on the inner surface of the upper end portion of the lower ring 031. Then, the piston rods of the hydraulic cylinders 03 are extended, the movement of the hydraulic cylinders 03 is transmitted to the upper metal mold 011 via the lower ring 030.fwdarw.the upper ring 031.fwdarw.the bolster 09.fwdarw.the upper heat insulator plate 010'.fwdarw.the upper heater plate 010. Thus, the upper metal mold 011 is lowered whereupon vulcanization of the green tire is carried out with the upper metal mold 011 kept in tight contact with the lower metal mold 07 under pressure. When the vulcanization has been finished, the piston rods of the hydraulic cylinders 03 are retracted thereby causing the lower ring 030 to release the engaged condition between the claws 030b provided on the inner surface of the upper end portion of the lower ring 030 and the claws 031b provided on the outer surface of the lower end portion of the upper ring 031. Subsequently, the piston rod of the hydraulic cylinder 032 is extended, whereby the upper ring 031 is rotated about its vertical axis in the direction opposite to that described above to disengage the claws 031b provided on the outer surface of the lower end portion of the upper ring 031 from the claws 030b provided on the inner surface of the upper end portion of the lower ring 030. Then, the piston rod of the hydraulic cylinder 034 is retracted to raise the bolster 09, the upper heat insulator plate 010', the upper heater plate 010, the upper metal mold 011 and the upper ring 031, whereby the upper metal mold 011 is separated from the lower metal mold 07. Subsequently, a vulcanized tire can be taken out from the inside of the lower metal mold 07.
What determines the quality of a tire vulcanized in the vulcanizing machine, is the preinflation (preliminary inflation called "shaping") of a green tire carried out when the upper metal mold 011 comes into tight contact with the lower metal mold 07. If a green tire is inflated too much, it may be possibly pinched between the upper metal mold 011 and the lower metal mold 07, while if the extent of inflation is too little, the green tire cannot be extended uniformly. Accordingly it is desirable to visually inspect the condition of the green tire up until just before the upper metal mold 011 and the lower metal mold 07 come into tight contact with each other. However, in the abovedescribed tire vulcanizing machine shown in FIG. 8, it is difficult to visually inspect the condition of a green tire because the upper ring 031 and the lower ring 030 are disposed outside of the upper metal mold 011 and the lower metal mold 07.